<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      //异步编程
      //后台控制输出 111  2s后输出222 3s后输出333
      function* gen() {
        yield one();
        yield two();
        yield three();
      }

      function one() {
        setTimeout(() => {
          console.log(111);
          iterator.next();
        }, 1000);
      }
      function two() {
        setTimeout(() => {
          console.log(222);
          iterator.next();
        }, 2000);
      }
      function three() {
        setTimeout(() => {
          console.log(333);
          iterator.next();
        }, 3000);
      }

      //调用函数生成器
      let iterator = gen();
      iterator.next();
    </script>
  </body>
</html>
